Crankshafts - are 948 and 1098 different?

Post by **don58van** » Sun Apr 12, 2009 1:54 pm

All

I will be rebuilding my 1098 which I bought stripped down. It looks like it needs a new crankshaft--significant scoring on some journals.

Hence my question.

Here in Oz, 1098s are fairly rare, as local production stopped soon after the 1098 motor was introduced. So it would be nice if I could find a good 948 crank to pop in.

I have studied my workshop manual, but it doesn't really answer my question.

Cheers
Don

Post by **PSL184** » Sun Apr 12, 2009 2:23 pm

I think the journals are a different size but someone will confirm or deny this. I would also guess the stroke is different. I guess you could always get one shipped from the UK?

Post by **paulk** » Sun Apr 12, 2009 7:31 pm

If you fit a 948 crank in a 1098 bore you end up with a 998cc engine.

Supposed to be very feasible but I've only heard about it not seen one.

All dependent on the mains being the same size. As long as the 1098's a normal Minor one they 'should' work.

BMC is the one to ask I'm sure he'll wander by shortly

Post by **bmcecosse** » Sun Apr 12, 2009 10:24 pm

Why not just regrind the 1098 shaft ?? But - yes you can fit a 948 crank - but then you must use 998 Mini pistons and rods. And indeed that will give you a 998 engine - which will rev nicely and with suitable camshaft and head /carb /exhaust modifictions will go very well!

Post by **don58van** » Sun Apr 12, 2009 11:00 pm

Thanks all

I was able to confirm from the workshop manual that the journals are the same size. I could not confirm that the stroke is the same and that other details are the same, such as the flywheel mount, etc.

BMC-the scoring is quite deep on several journals. I haven't taken it to an engine builder yet but it looks like I might be better off starting with a healthier one if I can get one at a reasonable cost. I know that the engine had been abused before I got it-- apart from the damage to the journals, one of the pistons had grabbed.

Cheers
Don

Post by **bmcecosse** » Mon Apr 13, 2009 8:28 pm

Well - the 948/1098 stoke is NOt the same - hence you can't use a 948 crank with your existing pistons. But 998 Mini pistons (and matching rods) will fit with 948 crank in that block - keep the 1098 camshaft, and witha decent head it will be good for ~ 55 bhp, but at highish revs !